What Goes Up Must Come Down
by AvianInk
Summary: When Ultron captures Natasha, he does more than keep her confined in a cage. After finding her, Bruce blacks out, Hulks out. He awakens in the aftermath with Tony by his side. (AOU canon divergent)


**[A/N] **This one was a Tumblr request. Thanks to everyone for the prompts, for reading, and feedback so lovely it makes my heart sing. 3

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Bruce awakens in a stiff bed, in a room not his, in a place that is not Sokovia nor Ultron's lair. An ache radiates from his brain to his skull, diffuses into his bones and tightens every muscle. Thinking and breathing are both trials. He has to endure the discomforting pressure of it in order to piece together where he lost himself in exchange for the other guy.

The first place his mind goes is to Natasha. He was supposed to get her out.

Completely unsure of who else, if anyone, is in the room, he asks, "Where…" After a cursory survey, he finds Tony at his bedside. "Where's Nat?"

Tony's posture—how he's hunched, condensed into an Atlas with the world's weight a shadow on his shoulders—it raises questions Bruce doesn't want answers to. He doesn't want those answers to be possibilities. Then he remembers.

The vast spectrum of red—organic, bright, glaring no matter how dry. A mizmaze of it—streaks, drops, stains—behind bars of a cage. Her, the motionless source.

Some nearby monitor beeps, warning of his escalating pulse. He doesn't need it to tell him what he knows, doesn't need the exacerbation. Except maybe he wants it, because that would push him faster into his other form, and nothing could stop the monster inside from ripping Ultron apart down to his wires. He'd go beyond that—he'd destroy every last database, screen, monitor, and hard drive to eradicate him. It wouldn't change what happened to Natasha—what Ultron did to her—but maybe, surely, if he let Hulk undigitize the planet, the chances of that brutality ever happening to her again would decrease. There had to be some saturation point when tyrants on this earth would stop inflicting their damage upon her.

"Hey." Tony's voice comes from a distance. It's like trying to sift marble through a sieve. The chirping of the monitor increases in tandem with his pulse and his willingness to compromise with the beast inside. Tony's not so on board with that. "We got Ultron. You got Ultron, the little witch got Ultron, the superbot got Ultron—everyone got Ultron."

He teeters on the brink, where every quickened breath is a straight injection of oxygen that his heart takes and pumps out to the latent muscles under his skin. It prepares to make him a monster and he has to tamp it down, his brain has to be strong enough to deny this, but that requires him to make certain of something. He strains to ask, "What about Nat?"

"She's alive." Tony's tone is not one that inspires hope. "She's sedated, but recovering. So don't do anything incredibly stupid. At least not green and stupid."

She's alive. Not okay, but alive. Out, but not unscathed. Why was it that her wellbeing was conditional—some karmic bargaining chip?

He could rebel against it. He could embrace a green fate. To do so would be to combine heedless tantrum with seismic mayhem, but he could do it. Seconds ago and even now, he's on the precipice. The difference between moments before and now is her, knowing she's safe and stable. Even if only for today, for the next hour, the world is safe, its breathing a little easier. He can't be what ends that. She wouldn't want it.

This room lacks a pair of headphones, lacks a blanket sturdier than the sterile, stiff one covering him. The medical equipment must've been a recent transport, the result of an unexpected surprise. He can't blame it, can't blame Tony or anyone else for not having the exact tools to diffuse him. Granted, even if he had those things on his lap, he'd want answers before he could endeavor to bring himself down.

Quiet is what he can manage. There is no alternative. Through a tensed jaw, he asks, "Where is she? Is she—how bad—"

"Don't make me answer that." Despite his attempt to veil it with nonchalance, the look Tony gives is fractured. In its cracks, Bruce can see the costs of victory, of this entire battle with an AI beast. It's plain to him, yet he doesn't know how to acknowledge it. Besides, Tony continues, getting to his feet and saying, half to himself, "She's gonna live. She'll probably hate me for the rest of her life, but I deserve that."

The acridity of it, though not directed at him, shoves him in the chest. It's a shallow jab between his ribs that resonates with a dissonance. Were he not so familiar with self-loathing, with the art of twisting every bitter outcome into his own doing, he wouldn't know what this is or where it came from. But punishing himself is something he's an expert in, more so than any branch of physics or biochemistry.

The world needed a suit of armor and it got Ultron. Tony was Einstein with the atom bomb.

Bruce tries to pull his friend back from the ledge he just stood at. "Tony—we couldn't control him. He went rogue—"

"No, but I could've listened to you. I could've put a pin in it, and I didn't." He puts distance between them and the conversation with quick strides toward the door. In the exit, he stops. Over his shoulder, in the silhouette of the hallway light, he says, "She's just down the hall. Clint's with her now." With a minute nod, Tony gestures to his right. "She'll probably ask for you when she wakes up. She's not gonna want to see me. Can't say I blame her."

"Tony—"

Then Tony does face him, but only to stick an arm out in a ceasefire signal. Grief stains every fissure and sunken hollow in his face. "Don't try to console me. Just...lay down and get better so you two can run off together."

Bruce has no chance to respond. Tony assures that when he shuts the door as he walks away.


End file.
